Question

The chloride of a metal contains 71% chlorine by weight and its vapour density is 50. The atomic mass of the metal will be (valency of the metal is 2):

• A. 29
• B. 58
• C. 35.5
• D. 71

Answer 1

The correct option is A 29

Assume metal is M and mass of metal is $x$ g.
As we know,
Molecular weight of compound $=2\times vapourdensity=2\times 50=100g$ ....... (1)
Also, valency of metal is $2$.
So, metal chloride is $MC{l}_2$
Molecular weight of metal chloride $=x+35.5\times 2=x+71$ $=100$ (from equation 1)
So, molecular weight of metal, $x$ $=100-71=29$ g/mol.